1. Field of the Invention
Devices, systems, and methods consistent with the invention relate to a method and apparatus automatically feeding wire, in particular welding wire.
2. Description of the Related Art
During the process of gas shielded MIG (metal inert gas) welding a MIG electrode (or MIG wire) is continuously paid off of a spool and passed to and through a welding gun. This is the case in both automatic and semi-automatic welding. Because the welding wire originates from a spool or bin of welding wire, at a point in time during the welding process the end of the wire is reached. When the wire is fully depleted the welding process must stop and a new spool, supply or bin of welding wire must be obtained.
When a new supply of welding wire is provided for the welding operation the wire must be initially fed through a wire feeder, or the like, to the welding gun. In most welding operations, a particular wire “stick out” length must be maintained to ensure a proper weld occurs. “Stick out” is a measure of the length of welding wire which extends from the contact tip of the welding gun. In related art systems, an operator must first feed the welding wire through the wire feeder and then continue to feed the wire until the operator believes he/she has provided sufficient wire for the “stick out.”
This process has its disadvantages. For example, in an automatic welding system the contact tip is typically located behind a protective barrier or shielding to protect the operator and prevent interference with the automated welding process. This results in an operator initiating the wire feeding operation at a remote distance from the contact tip and requires guessing as to when sufficient “stick out” is provided. The operator then must access the welding area to determine if the stick out length is proper. If the stick out is too long the operator must cut the excess off, while if the stick out is not sufficient the operator must return to the wire feeder control and repeat the process. The operation can be alternatively completed with two operators, but this results in an inefficient use of the operators' time and results in delay and operational down time.